1. Industrial Field of the Invention
This invention relates to a device for cleaning inner surfaces of heat exchanger tubes, and, more particularly to a device capable of cleaning inner surfaces of heat exchanger tubes, this device being suitably used in a turbine condensers and of a type which drives a cleaning brush thereof which serves as a cleaning member by fluid force.
2. PRIOR ART
At present, cleaning of each of instruments of a plant is performed at regular intervals during the routine inspection of fossil power plants and nuclear power plants. However, many of cleaning works need to be manually performed and are dangerous or tedious works under rather severe conditions. Therefore, an improvement of it by automating the work is desired.
The major cleaning work of the type described above in turbine cycles comprises cleaning work of tubes in a condenser which serves as a heat exchanger. A variety of methods of automating this work have been disclosed.
For example, a method of cleaning the inner surfaces of such heat exchanger tubes is known in which a cleaning brush thereof is moved from one end portion of the tube to the other end portion of the same by pressurized fluid supplied from an injection nozzle of a brush driving device. As a result of this, the inner surfaces of each of the tubes are successively and automatically cleaned by the cleaning brush (See Japanese Patent Unexamined Publication No. 61-72997 and Japanese Patent Unexamined Publication No. 61-205797).
Another example is known which is so constituted that a holding device in which a cleaning brush is disposed is respectively mounted on a space at each end of a plurality of heat exchanger tubes so that one or a plurality of these cleaning brushes are moved by pressurized fluid supplied by a driving device from one end portion of the tube to the other end portion of the same. Furthermore, the thus moved cleaning brushes are returned by the normal currents in the condenser or the same are reciprocated by supplying pressurized fluid in the reverse direction by way of turning the switch valve therein. As a result of this, one or a plurality of heat exchanger tubes are simultaneously cleaned (See Japanese Patent Unexamined Publication No. 55-8593 and Japanese Patent Unexamined Publication No. 60-38594).
However, if the inner surfaces of the heat exchanger tubes are cleaned in the former type of method, a great number of cleaning brushes, which are to be moved from one end portions of the tubes to the other end portions of the same by pressurized fluid, needs to be provided since a usual condenser includes approximately ten thousand of such heat exchanger tubes. Therefore, a particular method is required to automatically supply such cleaning brushes. Furthermore, large labor and excessive long time need to be taken to recover the large number of cleaning brushes after they have been used.
In a case where the latter method is employed, the cleaning brushes and the holding devices need to be provided by the number capable of cleaning the above-described large number of the heat exchanger tubes. Furthermore, the judging of the extent of wear of the cleaning brushes is difficult to be performed and exchange of the same cannot be carried out easily.
An object of the present invention is to provide a device for cleaning inner surfaces of heat exchanger tubes and which is capable of cleaning a multiplicity of heat exchanger tubes by a cleaning brush which is arranged to be moved in the heat exchanger tubes by pressurized fluid.
Another object of the present invention is to provide a device for cleaning inner surfaces of heat exchanger tubes and enabling readily changing cleaning brushes which are worn due to cleaning the inner surfaces of the heat exchanger tubes.
A further object of the present invention is to provide a device for cleaning inner surfaces of heat exchanger tubes and enabling determining the extent of wear of cleaning brushes which move in the heat exchanger tubes and the clogging conditions in the tubes.